The present invention relates to a product transporting apparatus of a type capable of transporting products successively from one station to another while they are received in and retained by respective tubular receptacles on a rotary drum which are communicated with a source of vacuum.
The U.S. Pat. No. 3,889,591, patented June 17, 1975, discloses the use of a product transporting apparatus in a printing machine for automatically printing indicia on the opposite surfaces of tablets, pills, candies or any other solid products of ay similar shape and/or size. The product transporting apparatus disclosed therein comprises first and second rotary drums of identical construction each having its outer peripheral surface formed with at least one circumferential row of radially inwardly recessed pockets arranged in circumferentially equally spaced relation to each other. The first and second rotary drums are adapted to be driven in the opposite directions with respect to each other, and the first rotary drum transports the products successively from a take-in position across a first printing station towards a transfer position where each of the pockets on the first rotary drum is lined up with a corresponding pocket on the second rotary drum for the transfer of the respective product from the first rotary drum onto the second rotary drum, and the second rotary drum transports the products, which have been transferred one by one from the first rotary drum, from the transfer position across a second printing station towards the take-out position.
The apparatus also comprises means for permitting some of the pockets to be communicated with the vacuum source of enabling the products to be sucked into and held in the corresponding pockets, and means for permitting the pockets to be successively communicated with a source of compressed air during the continued rotation of the rotary drum to enable the products so transported to be ejected onto a subsequent processing station at the take-out station. This U.S. patent also discloses the idea of centering, i.e., correctly positioning, each product within the associated pocket by allowing it to float in air by the effect of the blow of compressed air when the pocket carrying the product arrives, during the rotation of one of the rotary drums, at a top position immediately above the drive shaft of the associated rotary drum.